Again that would depend on doctrine. If NGD is going to be AAW-focused while NGF is more multipurpose (like Type 45 DDG & Type 26 FFG) then it would make sense to put AD-2 only on NGD.
12 NGF?
Where it says that? TPCR said 05-10 fir NGF & NGD combined. Meaning probably 6-7 NGF and 3-4 NGD...